Insulin-dependent diabetes mellitus affects millions of persons in the U.S. Despite years of intensive research, the effectiveness of current therapeutic regimens remains limited due to the difficulty of duplicating the glycemic control of a healthy pancreas. A potential method of treating this disease is the transplantation of allogenic or xenogenic islets of Langerhans. The most significant obstacle to the development of this approach is the immune rejection of the transplants. Immune-isolating islet encapsulation methodologies have been developed to solve this problem, but have been hampered by encapsulating materials evincing poor biocompatibility, poor permeability control, and insufficient mechanical durability. For this project, we propose to use photoactivatable synthetic polymers to prepare encapsulated islets. Synthetic polymers are being used increasingly in medical science due to their ability to be tailored to incorporate specific desirable properties, such as biocompatibility, permeability, and strength. Combining the use of synthetic polymers with the ability to photocrosslink in situ to form biocompatible gels provides us with a unique capability well suited for the encapsulation of pancreatic islets to provide immune protection. A successful demonstration of the ability to encapsulate islets in biocompatible synthetic polymer hydrogels will greatly increase the number and types of materials which can be evaluated for this purpose, and thus accelerate the development of the bio-artificial pancreas. PROPOSED COMMERCIAL APPLICATION: Insulin-dependent diabetes mellitus affects millions of persons in the U.S. The development of a technology which provides glycemic control to diabetic patients without the use of exogenous insulin will be of obvious interest to commercial interests and society at large.